JP6092887B2 - contact lens - Google Patents

Description

  The present invention relates to a contact lens, and more particularly to a contact lens having a novel edge shape and capable of realizing an excellent wearing feeling.

  2. Description of the Related Art Conventionally, contact lenses are provided that are worn on the surface of the cornea for the purpose of correcting myopia, hyperopia, and presbyopia. Of course, such contact lenses are required to have precision in optical properties and easy handling, but they are worn in contact with corneas and eyelids, which are sensitive biological tissues. Good wearing feeling is important.

  By the way, the contact lens has a substantially spherical crown shape as a whole, and a peripheral part is formed so as to surround the optical part formed in the central part, and an edge part is formed in the outermost peripheral part. Is provided. The curved concave lens inner surface and the curved convex lens outer surface are formed into a surface shape that is connected by an edge portion at each outer peripheral edge.

  The lens inner surface and lens outer surface are designed with a spherical surface having a radius of curvature corresponding to the corneal surface to achieve predetermined optical characteristics in the optical part and predetermined stability in the peripheral part. ing. Further, as described in Japanese Patent Publication No. 4-11085 (Patent Document 1), an edge portion connecting these lens inner surface and lens outer surface is tangent to both the outer peripheral edge of the lens inner surface and the outer peripheral edge of the lens outer surface. It is designed with a surface shape consisting of connecting arcs of a single radius of curvature that are connected in a direction.

  However, there are individual differences in the feeling of foreign matter when wearing the contact lens, and some wearers still complain that the contact lens with the conventional structure having the above-described surface shape has a large foreign object feeling. Therefore, further improvement in wearing feeling has been desired.

Japanese Patent Publication No.4-11085

  The present invention has been made in the background as described above, and a problem to be solved by the present invention is to provide a contact lens having a novel structure in which the feeling of wearing is further improved.

A first aspect of the present invention is a contact lens having a curved concave lens inner surface and a curved convex lens outer surface, and an inner surface arc extending in a tangential direction from the outer peripheral edge of the lens inner surface to the lens outer surface side; An outer surface arc extending tangentially from the outer peripheral end of the lens outer surface to the inner surface side of the lens is formed with a larger radius of curvature than a connecting arc connected in a tangential direction to both the outer peripheral end of the lens inner surface and the outer peripheral end of the lens outer surface And an angle of intersection at the connection point between the inner surface arc and the outer surface arc is made smaller than 180 degrees, and an edge portion connecting the outer peripheral end of the lens inner surface and the outer peripheral end of the lens outer surface is formed , and The radius of curvature of the inner surface arc is larger than the radius of curvature of the outer surface arc, and the type of the lens is a hard type, and the inner surface of the edge portion The connection point between the outer surface arc and arc is a smaller outer diameter than the cornea outer diameter inner surface arc is characterized in that it is allowed to position on the cornea.

  In order to solve the above problems, the present inventor has focused on the shape of the edge portion. That is, the edge portion of the conventional structure has a surface shape composed of a connecting arc having a single radius of curvature that is connected to the inner and outer surfaces of the lens in the tangential direction as described above, and has no intersection as a corner portion. Since the curved surface is smoothly connected to the cornea and the eyelid, it can be smoothly contacted with the cornea and the eyelid to prevent catching. However, considering that there are individual differences in the radius of curvature of the corneal surface, and that there is a positional difference in the radius of curvature even on the corneal surface of one eye, the edge portion of the corneal surface is worn on the cornea or eyelid when worn. It is easy to abut so as to be pressed. In particular, since the edge portion is the outer peripheral edge of the contact lens, there is a large difference in contact force between the contact portion of the edge portion pressed against the cornea or the eyelid and the portion where the edge portion is moved outward. This difference in contact force is considered to be one of the causes of foreign object feeling during wearing.

  The contact lens of the present embodiment completed based on such knowledge adopts an edge portion shape in which an inner surface arc and a outer surface arc having a larger radius of curvature than a connection arc of a conventional structure are connected at an angle smaller than 180 degrees. did. Then, each of the radial inclination angles of the edge portions extending from the inner and outer surfaces of the lens to the outer peripheral side is made smaller than the connecting arc of the conventional structure to have a surface shape that spreads gently. As a result, even when the edge portion is pressed against the cornea or the eyelid, a sudden change in the contact force at the pressed portion is alleviated, and a decrease in wearing feeling due to feeling the difference in the contact force as a foreign object sensation is reduced. be able to. In addition, the intersection angle at the connection point between the inner surface arc and the outer surface arc refers to an intersection angle (a depression angle) between the tangent line of the inner surface arc and the tangent line of the outer surface arc at the connection point.

On the other hand, in the contact lens of this aspect, there will be a connection point on the surface of the edge part, but as a result of examination by the present inventors, the contact lens is caught on the eyelid or cornea due to the presence of such a connection point, There were no inconveniences that exacerbated the foreign body sensation. This is because such a connection point exists not in the circumferential end portion of the edge portion but in the intermediate portion, so that it is considered difficult to directly press either the cornea or the eyelid.
Furthermore, in the contact lens of this aspect, considering that the cornea or eyelid of the human eye is a spherical surface having a center of curvature behind the eye, the radius of curvature of the inner surface arc on the cornea side is relatively large and The curvature radius of the outer surface arc on the eyelid side was made relatively small. This makes it possible to more effectively relieve the contact pressure of the edge portion on both the cornea side and the eyelid side during wearing.
Contact lenses are roughly classified into hard types and soft types. Unlike a soft type that deforms along the corneal surface when worn, hard type contact lenses that are rigid enough to maintain a substantially constant shape even when worn are affected by the edge being pressed against the cornea or eyelid during wearing. The contact pressure tends to increase, and there are many complaints that do not satisfy the feeling of wearing.
By applying the present invention to such a hard type contact lens, it is possible to greatly improve the wearing feeling as compared with a hard type contact lens having a conventional structure. In particular, according to the conventional technical idea, in a hard type contact lens, in order to prevent the cornea and the eyelid from being injured, it is natural that the surface of the edge portion has a smooth round edge shape over the entire surface. Therefore, according to the present invention, the technical idea of setting the connection point on the surface of the edge part to suppress the edge part surface inclination and improve the feeling of wearing is a new and innovative technical idea. The effect of improving the wearing sensation exhibited based on this has great technical significance.
Hard contact lenses are easier to handle astigmatism than soft contact lenses, can prevent the progression of corneal damage, and can be applied to orthokeratology. The present invention also has great technical significance in that technical effects that cannot be achieved can be achieved with good wearing feeling.

In the present invention , in the contact lens according to the first aspect, the inner arc and the outer arc are related to a straight line connecting the center of curvature of the inner arc and the connection point between the inner arc and the outer arc. A configuration having an asymmetric shape can be employed .

In the present invention, by adopting such a configuration, the contact pressure exerted on the cornea side and the contact pressure exerted on the eyelid side during wearing are adjusted by making the inner surface arc and the outer surface arc an asymmetric shape. It becomes possible. Therefore, the degree of freedom of adjustment according to the wearer is further increased, and the wearing feeling can be further improved.

In the present invention , in the contact lens employing the configuration described in [0012] above, a configuration in which the inner surface arc and the outer surface arc have different radii of curvature can be employed .

In the present invention, when such a configuration is adopted , the contact radius exerted on the cornea side during wearing and the contact exerted on the eyelid side are set by setting the radius of curvature of the inner surface arc and the outer surface arc to be relatively different. The contact pressure can be easily and effectively adjusted.

According to a second aspect of the present invention, in the contact lens according to the first aspect, a radius of curvature of the inner surface arc is set in a range of 0.035 mm to 0.050 mm.

  In the contact lens of this aspect, reduction of the contact pressure to the cornea in the inner surface arc of the edge portion, and thus improvement of wearing feeling can be achieved more effectively. In particular, when the radius of curvature of the inner surface arc is smaller than 0.035 mm, the inner surface arc of the edge portion rises abruptly, so that the contact pressure to the cornea tends to concentrate at the end of the inner surface arc on the connection side with the lens inner surface. The wearing feeling may be reduced. On the other hand, if the radius of curvature of the inner surface arc exceeds 0.050 mm, the rise of the inner surface arc of the edge portion is too slow, and the contact pressure with the cornea tends to concentrate at the end of the inner surface arc on the connection side with the outer surface arc. There is a risk that the feeling of wearing will be reduced.

According to a third aspect of the present invention, in the contact lens according to the first or second aspect, a lens defined on a radial line of the inner surface arc at a connection point between the outer peripheral end of the lens inner surface and the inner surface arc. The edge thickness is set within a range of 0.057 mm to 0.107 mm.

  When the thickness of the edge portion becomes smaller than 0.057 mm, the tip of the edge portion becomes pointed, and stimulation due to contact with the cornea or eyelids increases during lens displacement on the cornea during wearing, Wearing feeling may be reduced. On the other hand, if the thickness of the edge exceeds 0.107 mm, eyelid pressure acts greatly on the edge when it is sandwiched between the cornea and the eyelid during wearing, and irritation to the cornea and eyelid increases. As a result, the wearing feeling may be reduced.

According to a fourth aspect of the present invention, in the contact lens according to any one of the first to third aspects, the connection point between the inner surface arc and the outer surface arc is located on the outermost periphery of the lens. .

  The contact lens of this aspect has a technical effect that the inner arc and outer arc of the edge portion do not have an overhang shape in the optical axis direction of the lens, and thus manufacturing is relatively easy. In addition, since the pressing of the connection point to the cornea and the eyelid is avoided or reduced, it is effective for improving the wearing feeling.

According to a fifth aspect of the present invention, in the contact lens according to the fourth aspect, at the connection point between the inner surface arc and the outer surface arc, either the inner surface arc or the outer surface arc is the edge portion. An axial line that is in contact with the outer peripheral surface of the lens and extends parallel to the lens geometric center axis is a tangent.

  In the contact lens of this aspect, at the connection point, the inner surface arc or the outer surface arc is a contact arc in contact with the axial line, so that stimulation due to interference with the connection point of the eyelid that covers the connection point at the time of blinking or the like during wearing is performed. As a result, the feeling of wearing can be further improved.

A sixth aspect of the present invention is the contact lens according to the fifth aspect, wherein the outer surface arc is in contact with the outer peripheral surface of the edge portion at the connection point between the inner surface arc and the outer surface arc. An axial line extending parallel to the lens geometric center axis is a tangent.

  In the contact lens of this aspect, in the inner surface arc and the outer surface arc constituting the edge portion, the outer surface arc located on the lens outer surface side that the eyelid covers when worn is used as a tangential arc in contact with the axial line, thereby connecting the eyelids. Stimulation due to interference with points can be reduced more effectively.

  In the contact lens having the structure according to the present invention, the surface inclination of both the inner and outer surfaces at the edge portion can be suppressed to be small, and thereby the reduction of the contact force at the contact portion of the edge portion with the cornea and the eyelid can be promoted. Therefore, wearing feeling can be improved.

1 is a front view of a contact lens as a first embodiment of the present invention. The longitudinal cross-sectional view of the radial direction of the contact lens shown by FIG. The enlarged view of the edge part in FIG. The enlarged view of the edge part of the contact lens as 2nd embodiment of this invention. The enlarged view of the edge part in the contact lens of the conventional structure as a comparative example. The enlarged view of the edge part of the contact lens as a reference example of this invention. The graph which shows the test result of a wearing feeling together with the comparative example about the contact lens as Example 1 made into the structure according to 1st Embodiment shown by FIG. The graph which shows the test result of a wearing feeling together with the comparative example about the contact lens as Example 2 made into the structure according to 2nd Embodiment shown by FIG. The graph which shows the test result of a feeling of wear with a comparative example about the contact lens made into the structure according to the reference example shown by FIG.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  1 and 2 are a front view and a longitudinal sectional view of a contact lens 10 as a first embodiment of the present invention. The contact lens 10 has a substantially spherical crown shape as a whole, and as is well known, the contact lens 10 is used by being worn on the surface of the cornea in the eyeball. In the contact lens 10 according to the present embodiment, the lens geometric center axis 12 is an optical axis, and a rotating body around the lens geometric center axis 12 is used. Only the longitudinal section is shown.

  More specifically, the contact lens 10 of the present embodiment includes an optical unit 14 located at the center, a peripheral part 16 positioned around the optical part 14, and an edge part 18 positioned at the outermost peripheral part. It is composed of The optical unit 14 has optical characteristics that can give predetermined optical characteristics to the eye optical system of the wearer. The peripheral part 16 can position the contact lens 10 on the wearer's cornea so that the optical part 14 is positioned on the wearer's pupil. The edge portion 18 is a surface shape that protrudes radially outward, connecting the outer peripheral end of the curved concave lens inner surface 20 and the outer peripheral end of the curved convex lens outer surface 22 in the optical portion 14 and the peripheral portion 16. have.

  In the optical unit 14, optical characteristics for correcting vision based on the spherical lens power and the like can be appropriately set according to the optical characteristics of the eye optical system of the wearer. In the present invention, the optical characteristics set in the optical section 14 are not limited, and any optical characteristics can be set in the optical section 14. Although the outer diameter of the optical unit 14 is not limited, it is generally set to about φ3 to 9 mm in consideration of the wearer's cornea shape, assumed pupil diameter, and the like.

  The peripheral portion 16 has an annular shape with a predetermined width, and has a radial width dimension from the outer peripheral end of the optical portion 14 to the inner peripheral end of the edge portion 18. The outer diameter of the peripheral portion 16 is not limited, but in general, considering the distance between the upper and lower eyelids of the wearer and the lens stability on the cornea, the lens type of a hard type or a soft type is generally considered. It is set to about φ8 to 14 mm.

  The optical portion 14 and the peripheral portion 16 form a curved concave lens inner surface 20 and a curved convex lens outer surface 22 as a whole. Generally, a base curve surface having a radius of curvature corresponding to the cornea is set on the lens inner surface 20 of the optical unit 14 so as to be substantially similar to the surface of the wearer's cornea. The lens inner and outer surfaces 20 and 22 of the optical unit 14 are designed in consideration of the required optical characteristics and the required minimum thickness with reference to the base curve surface.

  In addition, the peripheral portion 16 has a radial surface shape that smoothly connects with the outer peripheral end of the optical portion 14 and the inner peripheral end of the edge portion 18 with a common tangent line on the inner and outer surfaces 20 and 22 of the lens. In general, the lens inner surface 20 of the peripheral portion 16 is a convex curved surface having a center of curvature on the outer side of the lens convex surface that is the front side of the lens in the radial section, while the lens outer surface 22 of the peripheral portion 16 is In the radial cross section, a convex curved surface having a center of curvature is formed on the outer side of the lens concave surface on the rear side of the lens. In addition to an arc shape in which a plurality of arcs having different curvature radii are connected, various shapes such as a polynomial shape and a conical curve shape are appropriately adopted for any of the radially curved surfaces.

  In addition, the lens inner and outer surfaces 20 and 22 of the peripheral portion 16 are set to have a curvature radius change point at a radially intermediate portion thereof, so that the radius of curvature at the outer peripheral portion is larger than the inner peripheral portion, or a substantially linear inclined surface. It can also be. By setting such a bevel surface on the outer peripheral portion of the peripheral portion 16, it becomes easy to set the edge lift with an appropriate size and to thin the outer peripheral portion of the peripheral portion 16.

  Note that the inner and outer peripheral ends of the peripheral portion 16 on the inner and outer surfaces 20 and 22 of the lens can be regarded as a change point of curvature. In particular, the boundary between the outer peripheral end of the optical portion 14 and the inner peripheral end of the peripheral portion 16. In some cases, a connection region that smoothly connects between them in the radial direction may be provided, and the boundary is not necessarily clear in terms of shape. On the other hand, the connection point between the outer peripheral edge of the peripheral portion 16 and the edge portion 18 on the inner and outer surfaces 20 and 22 of the lens can be recognized because the difference in curvature radius between the two is large.

  Here, an enlarged explanatory view of the radial section of the edge portion 18 including the connection points 24 and 26 between the outer peripheral edge of the peripheral portion 16 and the edge portion 18 on the inner and outer surfaces 20 and 22 of the lens is shown in FIG.

  As shown in FIG. 3, the edge portion 18 extends tangentially from the connection point 24, which is the outer peripheral end of the lens inner surface 20 of the peripheral portion 16, on the lens inner surface 20 side, and on the lens outer surface 22 side. It has an inner surface arc 28 that curves and extends so as to approach gradually. Further, the edge portion 18 is curved so as to extend in a tangential direction from the connection point 26 which is the outer peripheral end of the lens outer surface 22 of the peripheral portion 16 on the lens outer surface 22 side and gradually approach toward the lens inner surface 20 side. An extending outer surface arc 30 is provided.

  The inner surface arc 28 and the outer surface arc 30 are connected at the intersection point, and the surface of the edge portion 18 connecting the lens inner and outer surfaces 20 and 22 is formed by the inner and outer surface arcs 28 and 30. In addition, at the connection point 32 between the inner surface arc 28 and the outer surface arc 30, an intersection angle (a depression angle) formed by the tangents T1 and T2 of the inner surface arc 28 and the outer surface arc 30 is set to an angle smaller than 180 degrees. Yes. The intersection angle is desirably larger than 90 degrees, and more preferably set within a range of 154 degrees to 172 degrees.

  In particular, in this embodiment, as shown in FIG. 3, an axial line extending in parallel with the lens geometric center axis 12 in contact with the outer peripheral surface of the edge portion 18 at the connection point 32 between the inner surface arc 28 and the outer surface arc 30. The tangent lines T1 and T2 of the inner surface arc 28 and the outer surface arc 30 intersect X with a predetermined intersection angle α, β (α ≠ 0, β ≠ 0). In addition, the magnitudes of the intersection angles α and β may be the same or different.

  Both the inner surface arc 28 and the outer surface arc 30 are formed with a constant radius of curvature. That is, the inner surface arc 28 is an arc on a circle 36 around the inner surface arc center 34, while the outer surface arc 30 is an arc on a circle 40 around the outer surface arc center 38. In particular, in the present embodiment, both arc centers 34 and 38 are set inside the contact lens 10 in the longitudinal section. In FIG. 3, the circle 36 around the inner surface arc center 34 and the tangent line T1 of the inner surface arc 28 at the connection point 32 are indicated by broken lines. A circle 40 around the outer surface arc center 38 and a tangent line T2 of the outer surface arc 30 at the connection point 32 are indicated by a one-dot chain line.

  Furthermore, the curvature radius of the inner surface arc 28 and the curvature radius of the outer surface arc 30 may be set to different values or may be the same. However, if the difference between the radii of curvature of the inner and outer surface arcs 28 and 30 is too large, the position of the connection point 32 may be too close to either the lens inner surface 20 or the lens outer surface 22, and at the connection point 32. Since the angle of intersection of the tangents T1 and T2 of the inner and outer surface arcs 28 and 30 may be too small and sharp, the difference in curvature radius between the inner surface arc 28 and the outer surface arc 30 is 0.005 mm to 0.020 mm. It is desirable to set as follows.

  Further, the radius of curvature of the inner surface arc 28 and the radius of curvature of the outer surface arc 30 are both relative to both the connection point 24 that is the outer peripheral end of the lens inner surface 20 and the connection point 26 that is the outer peripheral end of the lens outer surface 22. The circumferential end portions 24 and 26 each have a larger radius of curvature than the connecting arc 42 that is close to a semicircle that is connected in the tangential direction. As a result, the connection point 32 between the inner surface arc 28 and the outer surface arc 30 is positioned at the outermost periphery of the lens, which is a tip end pointed like a bowl toward the radially outer side of the contact lens 10. In FIG. 3, the connection arc 42 is indicated by a two-dot chain line.

  Here, the curvature radii of the inner surface arc 28 and the outer surface arc 30 are appropriately set in consideration of the material of the contact lens 10, the thickness of the edge portion 18, the degree of perception of the wearer, and the like. It is desirable to set within the range of 0.050 mm. Further, the thickness dimension of the edge portion 18 is a lens defined by the thickness (the length of the line segment 44) extending in the radial direction of the inner surface arc 28 at the connection point 24 between the outer peripheral end of the lens inner surface 20 and the inner surface arc 28. It is desirable that the edge thickness is set within a range of 0.057 mm to 0.107 mm.

  Further, the inner surface arc center 34, which is the center of curvature of the inner surface arc 28, is biased toward the lens outer surface 22 side relative to the center of curvature 46 of the connection arc 42. On the other hand, the outer surface arc center 38, which is the center of curvature of the outer surface arc 30, is biased toward the lens inner surface 20 side with respect to the center of curvature 46 of the connection arc 42.

  The inner surface arc 28 extends from the connection point 24, which is the outer peripheral end of the lens inner surface 20, outward in the lens radial direction with a gentle inclination angle smaller than the connection arc 42, and reaches the connection point 32. The outer surface arc 30 also extends outwardly in the lens radial direction from the connection point 26, which is the outer peripheral end of the lens outer surface 22, to a connection point 32 with a gentle inclination angle smaller than that of the connection arc 42. Furthermore, the position of the connection point 32 that is the outermost peripheral end of the edge portion 18 is positioned so as to protrude outward in the lens radial direction from the outermost peripheral end of the connection arc 42.

  Further, in this embodiment, a line segment connecting the inner surface arc center 34 that is the center of curvature of the inner surface arc 28 and the connection point 32 with a straight line is defined as an edge protruding direction line 48, and the inner surface arc with respect to the edge protruding direction line 48 is defined. 28 and the outer surface arc 30 are asymmetrical. Also in such a structure, the connection arc 42 is different from the line-symmetrical shape with respect to one radial line passing through the center of curvature 46 thereof.

  In the contact lens 10 of the present embodiment including the edge portion 18 having the above-described structure, the radial inclination angle on the inner and outer surfaces of the edge portion 18 extending from the inner and outer surfaces 20 and 22 to the outer peripheral side is a connecting arc. It is set to be sufficiently smaller than 42. As a result, the inner surface arc 28 and the outer surface arc 30 of the edge portion 18 both extend in a tangential direction from the connection points 24 and 26 that are the outer peripheral ends of the lens inner and outer surfaces 20 and 22 toward the connection point 32 with a gentle inclination. It can be formed with a surface shape that spreads while being curved.

  Thereby, even when the surface of the inner surface arc 28 or the outer surface arc 30 of the edge portion 18 is pressed against the cornea or the eyelid when the contact lens 10 is worn, the abutting force accompanying the pressing is set wide and gently in the radial direction. The inner arc 28 and the outer arc 30 are dispersed. In this way, since the concentration and abrupt change of the contact force acting on the cornea and eyelid are alleviated by the inner and outer surface arcs 28 and 30 of the edge portion 18, a large change in the contact force and local change in the contact force is detected. As a result, it is possible to effectively reduce a decrease in wearing sensation due to the feeling of the feeling.

  In addition, since the connection point 32 existing on the surface of the edge portion 18 also exists in an intermediate portion in the round direction (inner and outer circumferential directions) of the edge portion 18 and protrudes outward in the radial direction of the contact lens 10. It is difficult to press directly against both the cornea and the eyelid. Therefore, such a connection point 32 does not cause problems such as catching on the eyelids or cornea, deterioration of foreign object feeling, or the like.

  Next, a contact lens 50 as a second embodiment of the present invention is shown in FIG. The contact lens 50 according to the present embodiment has the same basic structure as the contact lens 10 according to the first embodiment, and is an example of another aspect of the specific shape of the edge portion 18. Therefore, in the present embodiment, only an enlarged view of the edge portion in the lens radial direction cross section is illustrated, and a portion having the same structure as that of the first embodiment is shown in the drawing. The detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol as embodiment.

  That is, in the contact lens 10 of the first embodiment described above, the tangents T1 and T2 of the inner surface arc 28 and the outer surface arc 30 are both at a predetermined intersection angle with the axial line X at the connection point 32 of the edge portion 18. In the contact lens 50 of the present embodiment, the tangent line of the outer surface arc 30 is the axial line X at the connection point 32 of the edge portion 52, although they intersect with each other with α, β (α ≠ 0, β ≠ 0). On the other hand, the tangent line T1 of the inner surface arc 28 and the axial line X intersect with a predetermined intersection angle γ (γ ≠ 0). In short, at the connection point 32 between the inner surface arc 28 and the outer surface arc 30, the tangent line of the outer surface arc 30 is in contact with the outer peripheral surface of the edge portion 52 so as to be parallel to the lens geometric center axis 12. Is a tangent on the connection point 32 of the circle 40 around the outer surface arc center 38.

  In the present embodiment, the radius of curvature of the inner surface arc 28 is larger than the radius of curvature of the outer surface arc 30.

  As a result, the corner portion at the connection point 32 formed on the edge portion 52 is difficult to hit the eyelid side in particular, and the reduction in wearing feeling due to the pressing of the connection point 32 against the eyelid is further effectively reduced. Can be done.

  As mentioned above, although embodiment of this invention has been explained in full detail, this invention is not limitedly interpreted by the specific description in this embodiment and the below-mentioned Example.

  For example, not only a lens power for correcting myopia and hyperopia is set as an optical characteristic provided in the optical unit 14, but also a cylindrical lens for correcting astigmatism on either the inner or outer surface 20, 22 of the optical unit 14. The frequency may be set. Further, like a presbyopic contact lens, the optical center axis of the optical unit 14 may be set so as to be deviated with respect to the lens geometric center axis 12, and the contact lens according to the present invention is arranged around the lens geometric center axis 12. It need not be rotationally symmetric.

  Further, the present invention can be applied to a soft type contact lens and a hard type contact lens. In a conventional hard contact lens, it is common to adopt an arc shape that connects the inner and outer surfaces of the lens with a certain curvature as the edge shape, but in the present invention, such a conventional technical idea is It has a different and completely new technical idea. In other words, in a hard contact lens that tends to cause a foreign body sensation, the wearing feeling can be effectively improved by arbitrarily setting the curvature of the inner and outer surface arcs of the edge portion.

  In particular, the hard contact lens is used for correcting astigmatism and preventing the progression of corneal disorder, and a hard contact lens capable of exhibiting a good wearing feeling even in orthokeratologic has been demanded. Since the present invention can provide a hard contact lens with improved wearing feeling, it is recognized as having sufficient technical significance.

  Furthermore, the connection point 32 between the inner surface arc 28 and the outer surface arc 30 in the edge portion 18 need not have a sharp shape as illustrated in the embodiment. An aspect in which a chamfered surface is provided with a sufficiently small radius of curvature with respect to the apex of the connection point 32 may be adopted as necessary.

  In the above-described embodiment, a perfect circle is shown as the contact lens, but the contact lens is not limited to this, and may be oval. Furthermore, a contact lens by a truncation method in which a part of the outer periphery of the lens is linearly formed in the chord direction, a contact lens having a circumferential positioning effect in which a peripheral portion 16 is partially provided with a thick portion or a thin portion, etc. The present invention can be implemented.

  Furthermore, in the contact lens according to the present invention, the radii of curvature of the inner surface arc 28 and the outer surface arc 30 can be appropriately set in consideration of the shape of the wearer's cornea and the like, the tendency of discomfort, and the like. In a contact lens having a conventional semi-circular edge section having a constant radius of curvature, the shape of the edge section is uniquely determined from the thickness dimension of the edge section. In the contact lenses 10 and 50 of the present invention, the shape of the edge portions 18 and 52 can be arbitrarily set. That is, in the contact lens according to the present invention, it is possible to set the shape of the edge portion in consideration of individual differences of the wearer by appropriately adjusting the curvature radii of the inner and outer surface arcs 28 and 30, respectively. By expanding the degree of freedom of design and selection of the edge portions 18 and 52, it becomes possible to increase the degree of freedom of tuning of the shape of the edge portions 18 and 52 and the feeling of wear.

[Example]
The contact lenses 10 and 50 having the structure according to the first and second embodiments described above were manufactured as hard contact lenses, and a sensory test for wearing feeling was performed on these contact lenses. In each test, as shown in FIG. 5, a substantially semicircular connecting arc 42 having a single curvature radius connected to the outer peripheral ends 24 and 26 of the lens inner and outer surfaces 20 and 22 with a common tangent line. A contact lens having an edge portion was used as a comparative example, and the feeling of wearing was evaluated by comparison with the comparative example. A similar sensory test was also performed on the contact lens 54 having the structure shown in FIG. 6 that was manufactured for the purpose of confirming the technical effect of the present invention. The results of these tests are shown in FIGS. 7 to 9 as examples and reference examples.

[Example 1]
In Example 1, a contact lens 10 according to the structure of the first embodiment is manufactured as a test lens, and a comparative sensory test is performed between the test lens and a contact lens (comparative example) according to a conventional structure as a reference lens. did. In this test, the test lens and the control lens were sequentially worn on the left and right eyes for the 10 left and right eyes of 10 subjects, and the wearing feelings of the test lens and the control lens were compared immediately after wearing and 15 minutes after wearing. evaluated. In this test, the contact lenses worn on both the left and right eyes are the same, the wearing order of the contact lenses is random, and the subject cannot determine whether the wearing contact lens is the test lens or the control lens. It was. In the contact lens of Example 1 used in this test, the radius of curvature of the inner surface arc 28 is 0.035 mm, and the radius of curvature of the outer surface arc 30 is 0.035 mm. An arc having a radius of curvature of 0.035 mm was employed.

  FIG. 7 shows the test results of such a sensory test. From the graph of FIG. 7, it was confirmed that the wearing feeling of the contact lens 10 of Example 1 was superior to the contact lens of the comparative example immediately after wearing and 15 minutes after wearing.

[Example 2]
As Example 2, a contact lens 50 according to the structure of the second embodiment was made as a test lens, and a comparative sensory test with a control lens (Comparative Example) similar to Example 1 was performed. In this test, the left and right eyes of 17 subjects were worn with the test lens and the control lens, and the wearing feeling of the test lens and the control lens was compared and evaluated immediately after wearing and 15 minutes after wearing. did. In this test, the contact lenses worn on the left and right eyes are separate, the order of wearing the contact lenses is random, and the subject cannot determine whether the contact lens to be worn is the test lens or the control lens. It was. The contact lens of Example 2 used in this test has a radius of curvature of the inner arc 28 of 0.035 mm and a radius of curvature of the outer arc 30 of 0.030 mm. An arc having a radius of curvature of 0.035 mm was employed.

  FIG. 8 shows the test results of the sensory test. From the graph of FIG. 8, it was confirmed that the wearing feeling of the contact lens 50 of Example 2 was superior to that of the comparative contact lens immediately after wearing and 15 minutes after wearing.

[Reference example]
As a reference example, the contact lens 54 having the structure shown in FIG. 6 was prototyped as a hard contact lens, and a comparative sensory test with a control lens (comparative example) similar to that of Example 1 was performed. In addition, since this reference example differs in the shape of an edge part compared with the contact lens of Example 1, only the enlarged view of the edge part in a lens radial direction cross section is illustrated, and it is the same as that of Example 1. A detailed description of the structure is omitted.

  That is, in the contact lens 54 of this reference example, at the connection point 32 between the inner surface arc 28 and the outer surface arc 30 in the edge portion 56, both the tangent line of the inner surface arc 28 and the tangent line of the outer surface arc 30 are the axial line X. Has been. In short, at the connection point 32 between the inner surface arc 28 and the outer surface arc 30, the inner surface arc 28 and the outer surface arc 30 are connected with an axial line X extending parallel to the lens geometric center axis 12 of the contact lens 54 as a common tangent. Yes.

  In the present reference example, the radius of curvature of the inner surface arc 28 is smaller than the radius of curvature of the outer surface arc 30.

  In the test of the contact lens 54 as a reference example, the test lens and the control lens are worn on the left and right eyes of 12 subjects, and the test lens immediately after wearing and 15 minutes after wearing. The wearing feeling of the control lens was compared and evaluated. In this test, the contact lenses worn on the left and right eyes are separate, the order of wearing the contact lenses is random, and the subject cannot determine whether the contact lens to be worn is the test lens or the control lens. It was. The contact lens of the reference example used in this test has a radius of curvature of the inner surface arc 28 of 0.023 mm and a radius of curvature of the outer surface arc 30 of 0.030 mm. A 42 having a radius of curvature of 0.035 mm was employed.

  FIG. 9 shows the test results of the sensory test. From the graph of FIG. 9, no great difference in wear feeling was confirmed between the contact lens 54 of the reference example and the contact lens of the comparative example.

10, 50: contact lens, 12: lens geometric center axis, 18, 52: edge portion, 20: lens inner surface, 22: lens outer surface, 24: connection point (lens inner surface 20 outer peripheral edge), 26: connection point (lens outer surface) 22 outer peripheral end), 28: inner surface arc, 30: outer surface arc, 32: connection point, 34: inner surface arc center (inner surface arc 28 curvature center), 38: outer surface arc center (outer surface arc 30 curvature center), 42: connection arc , 46: center of curvature, 48: edge protruding direction line

Claims (6)

In a contact lens having a curved concave lens inner surface and a curved convex lens outer surface,
An inner surface arc extending tangentially from the outer peripheral edge of the lens inner surface to the lens outer surface side, and an outer surface arc extending tangentially from the outer peripheral edge of the lens outer surface to the lens inner surface side,
It is formed with a larger radius of curvature than a connecting arc connected in a tangential direction to both the outer peripheral edge of the lens inner surface and the outer peripheral edge of the lens outer surface,
The intersection angle between the inner surface arc and the outer surface arc is less than 180 degrees,
An edge portion connecting the outer peripheral end of the lens inner surface and the outer peripheral end of the lens outer surface is formed; and
The curvature radius of the inner surface arc is larger than the curvature radius of the outer surface arc, and the type of the lens is a hard type ,
The contact lens according to claim 1, wherein the connection point between the inner surface arc and the outer surface arc at the edge portion has an outer diameter smaller than the outer diameter of the cornea and the inner surface arc is positioned on the cornea .   The contact lens according to claim 1, wherein a radius of curvature of the inner surface arc is set in a range of 0.035 mm to 0.050 mm.   The lens edge thickness defined on the radial line of the inner surface arc at a connection point between the outer peripheral end of the inner surface of the lens and the inner surface arc is set in a range of 0.057 mm to 0.107 mm. Or the contact lens of 2.   The contact lens according to claim 1, wherein the connection point between the inner surface arc and the outer surface arc is located on the outermost periphery of the lens.   At the connection point between the inner surface arc and the outer surface arc, an axial line in which either the inner surface arc or the outer surface arc is in contact with the outer peripheral surface of the edge portion and extends in parallel with the lens geometric center axis is a tangent. The contact lens according to claim 4.   6. The axial line extending in parallel with the lens geometric center axis at the connection point between the inner surface arc and the outer surface arc is tangent to the outer surface arc in contact with the outer peripheral surface of the edge portion. contact lens.

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